Composite transistor

ABSTRACT

Disclosed herein is a composite transistor which includes a first transistor TR1 including a control electrode, a first active region, a first A extending part, and a first B extending part, and a second transistor TR2 including a control electrode, a second active region, a second A extending part, and a second B extending part. The first active region, the second active region, and the control electrode overlap one another. Both the first A extending part and the first B extending part extend from the first active region and both the second A extending part and the second B extending part extend from the second active region. The first electrode is connected to the first A extending part, the second electrode is connected to the second A extending part, and the third electrode is connected to the first B extending part and the second B extending part.

COSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/866,079, filed May 4, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/098,214, filed Nov. 1, 2018, now U.S. Pat. No.10,685,958, which is a national stage application under 35 U.S.C. 371and claims the benefit of PCT Application No. PCT/JP2017/012913 havingan international filing date of 29 Mar. 2017, which designated theUnited States, which PCT application claimed the benefit of JapanesePatent Application No. 2016-095194 filed 11 May 2016, the entiredisclosures of each of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a composite transistor, moreparticularly, a complementary transistor.

BACKGROUND ART

CMOS circuits in the past including inverter circuits, NAND circuits,etc. include field effect transistors, each having a field effecttransistor of p-channel type and a field effect transistor of n-channeltype which are arranged side by side. Attempts have been made to scaledown the layout of components, thereby increasing the gate density andreducing the power consumption. However, the scaling itself is becomingdifficult as the technique of fabrication becomes more sophisticated andthe manufacturing cost has been remarkably increasing.

One of the next-generation devices with low power consumption is thetunnel field effect transistor (TFET). The development of TFET hasattracted attention to the two-dimensional material (2D material) suchas Transition Metal DiChalcogenides (TMDC). An example of the TFET isdisclosed in Japanese Patent Laid-open No. 2015-090984. Thesemiconductor element disclosed in the Japanese Published UnexaminedPatent Application includes a semiconductor layer containing atwo-dimensional substance and at least one non-semiconductor layer on atleast one surface of the semiconductor layer, with the two-dimensionalsubstance including a first two-dimensional substance containing a firstmetal chalcogenide substance and a second two-dimensional substanceconnecting to the side of the first two-dimensional substance andcontaining a second metal chalcogenide substance, the firsttwo-dimensional substance and the second two-dimensional substance beingchemically bonded together.

CITATION LIST Patent Literature [PTL 1]

Japanese Patent Laid-open No. 2015-090984

SUMMARY Technical Problem

The TFET disclosed in Japanese Patent Laid-open No. 2015-090984,however, has a problem with difficulties in scaling as in the case offield effect transistors in the past.

Accordingly, the present disclosure is to provide a composite transistorwhich is so constructed as to achieve a higher density of integration.

Solution to Problem

The composite transistor of the present disclosure, which has beendeveloped to achieve the foregoing object, includes a first transistorincluding a control electrode, a first active region, a first Aextending part, and a first B extending part; and a second transistorincluding a control electrode, a second active region, a second Aextending part, and a second B extending part, in which the first activeregion, the second active region, and the control electrode overlap withone another in an overlapping region, each of the transistors has afirst electrode, a second electrode, and a third electrode, aninsulation layer is provided between the control electrode and one ofthe first active region and the second active region both adjacent tothe control electrode, each of the two transistors has the first Aextending part that extends from one end of the first active region, thefirst B extending part that extends from other end of the first activeregion, the second A extending part that extends from one end of thesecond active region, and the second B extending part that extends fromother end of the second active region, the first electrode connects tothe first A extending part, the second electrode connects to the secondA extending part, and the third electrode connects to the first Bextending part and the second B extending part. Note that the order ofoverlapping of the first active region, the second active region, andthe control electrode may be made in the order of the first activeregion, the second active region, and the control electrode or in theorder of the second active region, the first active region, and thecontrol electrode.

Advantageous Effects of Invention

The composite transistor according to the present disclosure includes afirst transistor and a second transistor in which the control electrode,the first active region, and the second active region overlap with oneanother. This structure leads to a higher density of integration. Notethat the effects mentioned herein are merely exemplary, and there willbe additional effects.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are conceptual diagrams depicting a composite transistoraccording to Example 1.

FIGS. 2A and 2B are schematic diagrams depicting an arrangement ofconstituents of an inverter circuit including the composite transistoraccording to Example 1. FIG. 2C is an equivalent circuit of the invertercircuit which includes the composite transistor according to Example 1.

FIG. 3 is a schematic partly cutaway sectional view of the compositetransistor according to Example 1.

FIGS. 4A to 4C are conceptual diagrams depicting a positional relationamong a first active region, a second active region, and a controlelectrode in the composite transistor according to Example 1.

FIGS. 5A to 5C are conceptual partly cutaway sectional views depictingthe composite transistor according to Example 1.

FIG. 6 is a schematic plan view of the composite transistor according toExample 1 and a schematic plan view of a CMOS circuit in the past, whichare intended to illustrate their footprint.

FIGS. 7A to 7C are a conceptual diagram depicting the compositetransistor according to Example 2.

FIGS. 8A and 8B are schematic partly cutaway sectional views of thecomposite transistor according to Example 2.

FIGS. 9A to 9C are conceptual diagrams depicting the compositetransistor according to Example 3.

FIG. 10 is a schematic partly cutaway sectional view of the compositetransistor according to Example 3.

FIG. 11A is an equivalent circuit of a NAND circuit which is formed onthe basis of the composite transistors according to Examples 1, 2, and3. FIGS. 11B and 11C are schematic diagrams depicting an arrangement ofconstituents of the NAND circuit including the composite transistoraccording to Example 1.

FIGS. 12A to 12C are conceptual partly cutaway sectional views of theNAND circuits formed on the basis of the composite transistors accordingto Example 1, Example 2, and Example 3, respectively.

FIG. 13 is a schematic diagram depicting the NAND circuit formed on thebasis of the composite transistor according to Example 1, with itsactive regions, etc. being cut along virtual planes at four levels.

FIGS. 14A and 14B are schematic diagrams each depicting the NAND circuitformed on the basis of the composite transistor according to Example 2and Example 3, respectively, with its active regions, etc. being cutalong virtual planes at two levels.

FIG. 15A is an equivalent circuit of a NOR circuit which is formed onthe basis of the composite transistors according to Example 1, Example2, and Example 3. FIGS. 15B and 15C are schematic diagrams depicting anarrangement of constituents of the NOR circuit including the compositetransistor according to Example 1.

FIGS. 16A to 16C are conceptual partly cutaway sectional views of theNOR circuits formed on the basis of the composite transistors accordingto Example 1, Example 2, and Example 3, respectively.

FIG. 17 is a schematic diagram depicting the NOR circuit formed on thebasis of the composite transistor according to Example 1, with itsactive regions, etc. being cut along virtual planes at four levels.

FIGS. 18A and 18B are schematic diagrams each depicting the NOR circuitformed on the basis of the composite transistor according to Example 2and Example 3, respectively, with its active regions, etc. being cutalong virtual planes at two levels.

FIG. 19 is a diagram depicting an equivalent circuit of an SRAM circuitincluding eight transistors formed on the basis of the compositetransistors according to Example 1, Example 2, and Example 3.

FIGS. 20A and 20B are schematic diagrams depicting an arrangement ofconstituents of the SRAM circuit including the composite transistoraccording to Example 1.

FIGS. 21A and 21B are conceptual partly cutaway sectional viewsdepicting the SRAM circuit formed on the basis of the compositetransistor according to Example 1.

FIGS. 22A and 22B are conceptual partly cutaway sectional viewsdepicting the SRAM circuit formed on the basis of the compositetransistor according to Example 2. FIGS. 22C and 22D are conceptualpartly cutaway sectional views depicting the SRAM circuit formed on thebasis of the composite transistor according to Example 3.

FIGS. 23A and 23B are schematic diagrams each depicting the SRAM circuitformed on the basis of the composite transistor according to Example 1,with its active regions, etc. being cut along virtual planes at fourlevels and one level.

FIGS. 24A to 24D are a schematic partly cutaway sectional views of asilicon semiconductor substrate which are intended to explain a methodfor producing the composite transistor according to Example 1.

FIGS. 25A to 25D are schematic diagrams depicting change in an energyband in each active region that occurs when conduction is turned on oroff in a composite transistor including a first structure or a secondstructure of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The present disclosure will be described in more detail with referenceto the following examples, which are not intended to restrict the scopethereof. The various numerical values and materials depicted in Examplesare merely exemplary. The following description will proceed in theorder listed below.

1. General description of composite transistor according to presentdisclosure2. Example 1 (Composite transistor of first structure according topresent disclosure)3. Example 2 (Modification to Example 1 of second structure accordingpresent disclosure)4. Example 3 (Another modification to Example 1 of third structureaccording to present disclosure)5. Example 4 (Applications of composite transistor according to presentdisclosure)

6. Others General Description of Composite Transistor According toPresent Disclosure

A composite transistor of the present disclosure has a first electrode,a second electrode, and a control electrode.

The first electrode is given a higher voltage than that which is givento the second electrode.

When the control electrode is given a first voltage V₁, a firsttransistor becomes conductive and a second transistor becomesnon-conductive, and

when the control electrode is given a second voltage V₂ (which is higherthan the first voltage V₁), the second transistor becomes conductive andthe first transistor becomes non-conductive.

The composite transistor including preferred mode of the presentdisclosure additionally has a first active region and a second activeregion, which include a two-dimensional material or graphene.

The composite transistor including preferred mode of the presentdisclosure above is constructed as follows.

The composite transistor has an overlapping region in which the firstactive region includes a first A active region and a first B activeregion overlapping with the first A active region.

The composite transistor has a first A extending part which extends fromthe first A active region, and also has a first B extending part whichextends from the first B active region.

In the overlapping region, the second active region includes a second Aactive region and a second B active region overlapping with the second Aactive region.

The composite transistor has a second A extending part which extendsfrom the second A active region, and also has a second B extending partwhich extends from the second B active region.

The first A active region differs from the first B active region inenergy values as defined below.

E_(V-1A)<E_(V-1B)E_(C-1A)<E_(C-1B)where E_(V-1A) denotes the energy value at the upper end of the valenceband of the first A active region;

E_(C-1A) denotes the energy value at the lower end of the conductionband of the first A active region;

E_(V-1B) denotes the energy value at the upper end of the valence bandof the first B active region; and

E_(C-1B) denotes the energy value at the lower end of the conductionband of the first B active region.

The second A active region differs from the second B active region inenergy values as defined below.

E_(V-2A)>E_(V-2B)E_(C-2A)>E_(C-2B)where E_(V-2A) denotes the energy value at the upper end of the valenceband of the second A active region;

E_(C-2A) denotes the energy value at the lower end of the conductionband of the second A active region;

E_(V-2B) denotes the energy value at the upper end of the valence bandof the second B active region; and

E_(C-2B) denotes the energy value at the lower end of the conductionband of the second B active region. Incidentally, the compositetransistor constructed as mentioned above will be referred to as “acomposite transistor of a first structure according to the presentdisclosure” for the sake of convenience.

It satisfies the following conditions when the composite transistor isoff:

E_(C-1B)>E_(C-1A)>E_(V-1B)>E_(V-1A), andE_(C-2A)>E_(C-2B)>E_(V-2A)>E_(V-2B)

That is, it satisfies the following conditions when the compositetransistor is on:

E_(C-1B)>E_(V-1B)>E_(C-1A)>E_(V-1A), andE_(C-2A)>E_(V-2A)>E_(C-2B)>E_(V-2B)

The first A active region and the first B active region may overlap inany manner; for example, the first A active region may be adjacent tothe control electrode or the first B active region may be adjacent tothe control electrode. Likewise, the second A active region and thesecond B active region may overlap in any manner; for example, thesecond A active region may be adjacent to the control electrode or thesecond B active region may be adjacent to the control electrode.

Then, the composite transistor including the first structure of thepresent disclosure above may be constructed for stable operation suchthat a second insulation layer is interposed between the first activeregion and the second active region. Moreover, it may be constructed forstable operation such that a first interlayer insulation layer isinterposed between the first A active region and the first B activeregion, and a second interlayer insulation layer is interposed betweenthe second A active region and the second B active region. However, thesecond insulation layer, the first interlayer insulation layer, and thesecond interlayer insulation layer are not necessarily essential. Theremay be an instance in which the second insulation layer, the firstinterlayer insulation layer, and the second interlayer insulation layerare not necessary if the first A active region and the first B activeregion are made to change in energy band between them, and the second Aactive region and the second B active region are made to change inenergy band between them based on the application of voltage to thecontrol electrode which is mentioned later. These insulation layers maybe a single layer of natural oxide or a laminate layer bonded togetherthrough van der Waals force.

Alternatively, the composite transistor including preferred mode of thepresent disclosure above is constructed as follows.

The composite transistor has an overlapping region in which a firstactive region includes a first A active region and a first B activeregion which is on the same virtual plane as the first A active regionand is opposite to the first A active region.

The composite transistor has a first A extending part which extends fromthe first A active region, and also has a first B extending part whichextends from the first B active region.

In the overlapping region, the second active region includes a second Aactive region and a second B active region which is on the same virtualplane as the second A active region and is opposite to the second Aactive region.

The composite transistor has a second A extending part which extendsfrom the second A active region, and also has a second B extending partwhich extends from the second B active region.

The first A active region differs from the first B active region inenergy values as defined below.

E_(V-1A)<E_(V-1B)E_(C-1A)<E_(C-1B)where E_(V-1A) denotes the energy value at the upper end of the valenceband of the first A active region;

E_(C-1A) denotes the energy value at the lower end of the conductionband of the first A active region;

E_(V-1B) denotes the energy value at the upper end of the valence bandof the first B active region; and

E_(C-1B) denotes the energy value at the lower end of the conductionband of the first B active region.

The second A active region differs from the second B active region inenergy values as defined below.

E_(V-2A)>E_(V-2B)E_(C-2A)>E_(C-2B)where E_(V-2A) denotes the energy value at the upper end of the valenceband of the second A active region;

E_(C-2A) denotes the energy value at the lower end of the conductionband of the second A active region;

E_(V-2B) denotes the energy value at the upper end of the valence bandof the second B active region; and

E_(C-2B) denotes the energy value at the lower end of the conductionband of the second B active region. Incidentally, the compositetransistor constructed as mentioned above will be referred to as “acomposite transistor of a second structure of the present disclosure”for the sake of convenience.

That is, it satisfies the following conditions when the composite isoff:

E_(C-1B)>E_(C-1A)>E_(V-1B)>E_(V-1A), andE_(C-2A)>E_(C-2B)>E_(V-2A)>E_(V-2B)

It satisfies the following conditions when the composite is on:

E_(C-1B)>E_(V-1B)>E_(C-1A)>E_(V-1A), andE_(C-2A)>E_(V-2A)>E_(C-2B)>E_(V-2B)

The composite transistor of the second structure of the presentdisclosure above may be constructed for stable operation such that asecond insulation layer is interposed between the first active regionand the second active region. It is to be noted that the secondinsulation layer is not always essential. There may be an instance inwhich the second insulation layer is not necessary if the first A activeregion and the first B active region are made to change in energy bandbetween them, and the second A active region and the second B activeregion are made to change in energy band between them based on theapplication of voltage to the control electrode which is mentionedlater. The second insulation layer may be a single layer of naturaloxide or a laminate layer bonded together through van der Waals force.

The composite transistor of the present disclosure may also beconstructed as follows.

The composite transistor has an overlapping region in which a firstactive region includes a first channel forming region, a first Aextending region extends from one end of the first channel formingregion, and a first B extending region extends from the other end of thefirst channel forming region, and the composite transistor also has anoverlapping region in which a second active region includes a secondchannel forming region, a second A extending region extends from one endof the second channel forming region, and a second B extending regionextends from the other end of the second channel forming region.

When the control electrode is given a second voltage V₂ (which is higherthan the first voltage V₁) the second transistor becomes conductive andthe first transistor becomes non-conductive. Incidentally, the compositetransistor constructed as mentioned above will be referred to as “acomposite transistor of a third structure of the present disclosure” forthe sake of convenience.

The composite transistor including the third structure of the presentdisclosure above may additionally have a second insulation layer betweenthe first active region and the second active region. In the compositetransistor including the third structure of the present disclosureincluding such a structure, the first active region and the secondactive region may preferably include a two-dimensional material orgraphene.

The composite transistor including preferred various modes andconfigurations of the present disclosure described above will begenerally and simply referred to as “Composite transistor disclosedherein” hereinafter. It may be constructed such that the first electrodeis given a higher voltage than that which is given to the secondelectrode. Specifically, the first electrode is given the second voltageV₂ (or V_(dd) volt>0) and the second electrode is given the firstvoltage V₁ (or 0 volt). Incidentally, the first voltage V₁ and thesecond voltage V₂ applied to the control electrode are based on thefirst A active region and the second A active region as the reference.

The composite transistor including the first structure and the secondstructure according to the present disclosure function in the followingmanner. When the control electrode is given the first voltage V₁ (whichis lower than the second voltage V₂), the first A active region as aconstituent of the first transistor is given the second voltage V₂, forexample. This makes the first transistor to change in energy values asfollows. Assume that a first boundary region between the first A activeregion and the first B active region has the valence band whose energyvalue is E_(V-1-IF) at its upper end and also has the conduction bandwhose energy value is E_(C-1-IF) at its lower end. Assume also that thefirst B active region has the valence band whose energy value isE_(V-1B) at its upper end and also has the conduction band whose energyvalue is E_(C-1B) at its lower end. Then, it follows that former twovalues approach the latter two values, respectively. (See FIG. 25B.) Theconsequence is the movement of electrons, due to tunnel effect, from thefirst B active region to the first A active region. This in turn makesthe first transistor conductive and causes the first A active region andthe first B active region to have ideally the same potential, whichmakes the third electrode have the same potential as the secondpotential V₂. On the other hand, the second transistor has the second Aactive region given the first voltage V₁ and also has the controlelectrode given the first voltage V₁. The result is that the secondtransistor remains unchanged in the energy value E_(V-2-IF) of thevalence band at its upper end and the energy value E_(C-2-IF) of theconduction band at its lower end in a second boundary region between thesecond A active region and the second B active region. (See FIG. 25C.)The consequence is the absence of electron movement from the second Aactive region to the second B active region, which keeps the secondtransistor non-conductive.

Also, the composite transistor including the first structure and thesecond structure according to the present disclosure function in thefollowing manner. When the control electrode is given the second voltageV₂ (which is higher than the first voltage V₁), the second A activeregion as a constituent of the second transistor is given the firstvoltage V₁. This makes the second transistor to change in energy valuesas follows. Assume that the second boundary region between the second Aactive region and the second B active region has the valence band whoseenergy value is E_(V-2-IF) at its upper end and also has the conductionband whose energy value is E_(C-2-IF) at its lower end. Assume also thatthe second B active region has the valence band whose energy value isE_(V-2B) at its upper end and also has the conduction band whose energyvalue is E_(C-2B) at its lower end. Then, it follows that former twovalues approach the latter two values, respectively. (See FIG. 25D.) Theconsequence is the movement of electrons (due to tunnel effect) from thesecond A active region to the second B active region. This in turn makesthe second transistor conductive and causes the second A active regionand the second B active region to have ideally the same potential, whichmakes the third electrode have the first potential V₁. On the otherhand, the first transistor has the first A active region given thesecond voltage V₂ and also has the control electrode given the secondvoltage V₂. The result is that the first transistor remains unchanged inthe energy value E_(V-1-IF) of the valence band at its upper end and theenergy value E_(C-1-IF) of the conduction band at its lower end in thefirst boundary region between the first A active region and the first Bactive region. (See FIG. 25A.) The consequence is the absence ofelectron movement from the first A active region to the first B activeregion, which keeps the first transistor non-conductive.

The composite transistor including the first structure and the secondstructure according to the present disclosure is regarded as including afirst transistor corresponding to an FET of p-channel type and a secondtransistor corresponding to an FET of n-channel type. In addition, ithas the first A active region and the second A active region eachcorresponding to the source in FET. It has the first B active region andthe second B region each corresponding to the drain in FET. It has thecontrol electrode corresponding to the gate in FET. The compositetransistor including the first structure and the second structureaccording to the present disclosure may have the first A active regionand the second B active region referred to as “n-type active region” andalso have the first B active region and the second A active regionreferred to as “p-type active region” for the sake of convenience.

The composite transistor including the third structure of the presentdisclosure basically functions in the same way as the field effecttransistor in the past.

The composite transistor of the present disclosure has the overlappingregion in which the first active region and the control electrodeoverlap each other. In this case, the first active region may have itsorthogonal projection image which is surrounded by that of the controlelectrode, or which coincides with that of the control electrode, orwhich projects from that of the control electrode. Likewise, it has theoverlapping region in which the second active region and the controlelectrode overlap each other. In this case, the second active region mayhave its orthogonal projection image which is surrounded by that of thecontrol electrode, or which coincides with that of the controlelectrode, or which projects from that of the control electrode.

In addition, the composite transistor including the first structure ofthe present disclosure has the overlapping region in which the first Aactive region and the first B active region constituting the firstactive region overlap each other. In this case, the region where thefirst A active region and the first B active region overlap each othermay have its orthogonal projection image which is surrounded by that ofthe control electrode, or which coincides with that of the controlelectrode, or which projects from that of the control electrode.Likewise, it has the overlapping region in which the second A activeregion and the second B active region constituting the second activeregion overlap each other. In this case, the region where the second Aactive region and the second B active region overlap each other has itsorthogonal projection image which is surrounded by that of the controlelectrode, or which coincides with that of the control electrode, orwhich projects from that of the control electrode.

The composite transistor of the present disclosure should preferably beconstructed such that the first A extending part and the first Bextending part extend in the same direction as the second A extendingpart and the second B extending part extend.

The composite transistor including the first structure and the secondstructure of the present disclosure may have four, three, or two activeregions which include different materials as follows.

[A] Four different kinds of materials for the first A active regionincluding the first A extending part, the first B active regionincluding the first B extending part, the second A active regionincluding the second A extending part, and the second B active regionincluding the second B extending part.[B] One kind of material for the first A active region and the second Bactive region, and two kinds of materials for the first B active regionand the second A active region.[C] Two kinds of materials for the first A active region and the secondB active region and one kind of material for the first B active regionand the second A active region.[D] One kind of material for the first A active region and the second Bactive region and one kind of material for the first B active region andthe second A active region.

In the case where the first A active region and the second B activeregion include different materials, it is possible to form the first Aactive region and the second B active region from the same materialwhich is doped with different dopants. Likewise, in the case where thefirst B active region and the second A active region include differentmaterials, it is possible to form the first B active region and thesecond A active region from the same material which is doped withdifferent dopants. Doping may be accomplished by ion injection orchemical doping.

Examples of the dopant for the p-type active region include thefollowing.

Ionic solutions such as NO₂BF₄, NOBF₄, and NO₂SbF₆.

Acids such as HCl, H₂PO₄, CH₃COOH, H₂SO₄, and HNO₃.

Organic composites such as dichlorodicyanoquinone, oxone,dimyristoylphosphathidylinositol, and trifluoromethanesulfoneimide.

HPtCl₄, AuCl₃, HAuCl₄, silver trifluoromethanesulfonate, AgNO₃, H₂PdCl₆,Pd(OAc)₂, and Cu(CN)₂.

In addition, examples of the dopant for the n-type active region includethe following.

NMNH (nicotinamide mononucleotide-H), NADH (nicotinamide adeninedinucleotide-H), NADPH (nicotinamide adenine dinucleotide phosphate-H),PEI (polyethyleneimine), and alkali metals (such as potassium andlithium).

The composite transistor of the present disclosure may have the firstactive region and the second active region which include atwo-dimensional material, as mentioned above. Its typical exampleincludes TMDC (Transition Metal DiChalcogenide). TMDC is represented byMX₂, where M denotes a transition metal such as Ti, Zr, Hf, V, Nb, Ta,Mo, W, Tc, and Re, and X denotes a chalcogen such as O, S, Se, and Te.The TMDC also includes CuS, which is a composite including Cu(transition metal) and S (chalcogen), or includes a composite includinga nontransition metal and a chalcogen, the former including Ga, In, Ge,Sn, and Pb. Such composite may be exemplified by GaS, GaSe, GaTe,In₂Se₃, InSnS₂, SnSe₂, GeSe, SnS₂, and PbO. Moreover, the compositetransistor of the present disclosure may have the first and secondactive regions including a two-dimensional material such as blackphosphorus.

The two-dimensional material exemplified below may be used for the firstA active region or the second B active region (n-type active region) inthe composite transistor including the first and second structures ofthe present disclosure. The two-dimensional material exemplified belowmay also be used for the second A extending part and the second Bextending part in the composite transistor including the third structureof the present disclosure. At least one kind of two-dimensional materialselected from the group including MoSe₂, MoTe₂, WSe₂, MoS₂, and WTe₂,which have a thickness of 0.65 to 6.5 nm, preferably 0.65 to 2.6 nm. Onthe other hand, the two-dimensional material exemplified below may beused for the first B active region or the second A active region (p-typeactive region) in the composite transistor including the first andsecond structures of the present disclosure. The two-dimensionalmaterial exemplified below may also be used for the first A extendingpart and the first B extending part in the composite transistorincluding the third structure of the present disclosure. At least onekind of two-dimensional material selected from the group including MoS₂,WS₂, ZrS₂, ZrSe₂, HfS₂, HfSe₂, NbSe₂, and ReSe₂, which have a thicknessof 0.65 to 6.5 nm, preferably 0.65 to 2.6 nm. The foregoing examples arenot intended to restrict the scope of the disclosure.

In the case where the first A active region and the second B activeregion include different kinds of two-dimensional material, thetwo-dimensional material for the first A active region is represented byM^(1A)X^(1A) ₂ and the two-dimensional material for the first B activeregion is represented by M^(1B)X^(1B) ₂, where:

M^(1A)≠M^(1B) and X^(1A)≠X^(1B), orM^(1A)=M^(1B) and X^(1A)≠X^(1B), orM^(1A)≠M^(1B) and X^(1A)=X^(1B).

Likewise, the two-dimensional material for the second A active region isrepresented by M^(2A)X^(2A) ₂ and the two-dimensional material for thesecond B active region is represented by M^(2B)X^(2B) ₂, where:

M^(2A)≠M^(2B) and X^(2A)≠X^(2B), orM^(2A)=M^(2B) and X^(2A)≠X^(2B), orM^(2A)≠M^(2B) and X^(2A)=X^(2B).

The foregoing examples are not intended to restrict the scope of thedisclosure.

There are several methods for forming the first A active region, thefirst B active region, the second A active region, and the second Bactive region. They include PVD method and CVD method as well as thosementioned below.

[a] One including steps of preparing a precursor of transition metalchalcogenite, applying the precursor onto the substrate to form a thinfilm thereon, and performing heart treatment.[b] One including steps of coating the substrate with a thin film of atransition metal oxide and causing the transition metal in thetransition metal oxide to react with a chalcogen in a materialcontaining a chalcogen element.

The term “graphene” mentioned above denotes a sheet-like substance ofcarbon atoms with sp² bond, having a thickness equal to one atom. It hasa hexagonal lattice structure, like honeycomb, including carbon atomsbinding together. The graphene film can be doped with an n-type orp-type impurity by chemical doping. The chemical doping is accomplishedby coating the graphene film with a dopant layer. The dopant layer maybe that of electron accepting type (or p-type) or that of electrondonating type (or n-type). The dopant layer of electron accepting type(or p-type) may include chlorides (such as AuCl₃, HAuCl₄, and PtCl₄),acids (such as HNO₃, H₂SO₄, HCl, and nitromethane), Group III elements(such as boron and aluminum), and oxygen, which are electron attractingmolecules. The dopant layer of electron donating type (or n-type) mayinclude Group V elements (such as nitrogen and phosphorus), pyridinecomposites, nitrides, alkali metals, and aromatic composites havingalkyl groups, which are electron-donating molecules.

Graphene may be produced by the following method. First, a base iscoated with a film containing a graphenizing catalyst. Then, the filmcontaining a graphenizing catalyst is provided with a gas-phase carbonsource. This step is followed by heat treatment to grow graphene.Finally, the resulting graphene is cooled at a prescribed rate. In thisway, it is possible to coat the film containing a graphenizing catalystwith film-like graphene. The graphenizing catalyst includes, forexample, carbon composites (such as SiC) and at least one kind of metalselected from the group including Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg,Mn, Mo, Rh, Si, Ta, Ti, W, U, V, and Zr. The gas-phase carbon sourceincludes, for example, at least one species of carbon source selectedfrom the group including carbon monoxide, methane, ethane, ethylene,ethanol, acetylene, propane, butane, butadiene, pentane, pentene,cyclopentadiene, hexane, cyclohexane, benzene, and toluene. The thusformed film-like graphene is separated from the film containing agraphenizing catalyst. In this way there is obtained graphene asdesired.

The composite transistor including the first structure of the presentdisclosure has two active regions as mentioned above. The first A activeregion and the first B active region overlap with each other, and theymay be in contact with each other or they may be separated from eachother, with the first boundary region interposed between them. Likewise,the second A active region and the second B active region overlap witheach other, and they may be in contact with each other or they may beseparated from each other, with the second boundary region interposedbetween them. The first and second boundary regions may include thefirst interlayer insulation layer and the second interlayer insulationlayer as mentioned above.

The composite transistor including the second structure of the presentdisclosure has two active regions as mentioned above. The first A activeregion and the first B active region face each other, and they may be incontact with each other or they may be separated from each other, with afirst boundary region interposed between them. Likewise, the second Aactive region and the second B active region face each other, and theymay be in contact with each other or they may be separated from eachother, with the second boundary region interposed between them. Thefirst and second boundary regions may include such materials as SiO₂(including natural oxide film), SiN, hexagonal boron nitride (hBN), andA1 ₂O₃.

The composite transistor of the present disclosure has the controlelectrode which includes any one of such materials as polysilicon,polycide, metallic silicide, metal nitride (e.g., TiN), metals (e.g.,aluminum (Al) and gold (Au)), graphene, and ITO. The control electrodemay be formed by any one of such methods as physical vapor deposition(PVD method), including vacuum vapor deposition and sputtering, andchemical vapor deposition (CVD method). The first to third electrodesmay include any one of such conductive materials as impurity-dopedpolysilicon, aluminum, and high-melting point metals and metal silicidesincluding tungsten, Ti, Pt, Pd, Cu, TiW, TiNW, WSi₂, and MoSi₂. Thecontrol electrode may be formed by PVD method or CVD method.

Moreover, the insulation layer and the second insulation layer includesuch materials as SiO₂, SiOF, SiN, and SiON, as well as those materialswith a high dielectric constant k (ϵ/ϵ₀≥4.0). Examples of the highdielectric materials include metal oxides and metal nitrides, such ashafnium oxide (HfO₂), zirconium oxide (ZrO₂), aluminum oxide (Al₂O₃),aluminum-hafnium oxide (HfAlO₂), silicon-hafnium oxide (HfSiO), tantalumoxide (Ta₂O₅), yttrium oxide (Y₂O₃), and lanthanum oxide (La₂O). Theyalso include insulation materials of metal silicate such as HfSiO,HfSiON, ZrSiO, AlSiO, and LaSiO. The insulation layer and the secondinsulation layer may include one kind of material or more than one kindof materials. Also, the insulation layer and the second insulation layermay be of monolayer structure or multiplelayer structure. The insulationlayer and the second insulation layer may be formed by any one of theCVD methods including ALD (Atomic Layer Deposition) and MOCVD(organometal vapor phase deposition), or the PVD methods includingvacuum vapor deposition and sputtering. The insulation layer may have athickness ranging from 1 to 10 nm, and the second insulation layer mayhave a thickness ranging from 1 to 10 nm.

The first interlayer insulation layer and the second interlayerinsulation layer may include SiO₂, SiN, hexagonal boron nitride (hBN),and Al₂O₃. The first interlayer insulation layer and the secondinterlayer insulation layer may be formed by low-temperature oxidationmethod, plasma CVD method, and ALD method. The first interlayerinsulation layer and the second interlayer insulation layer may have athickness ranging from 1 to 3 nm.

The composite transistor of the present disclosure may be formed on asilicon semiconductor substrate coated with an insulation film.

The composite transistor of the present disclosure may be used toconstruct complementary transistors and logical circuits (such asinverter circuits, NAND circuits, AND circuits, NOR circuits, ORcircuits, XOR circuits, and NOT circuits) and also memories such asSRAM.

Example 1

Example 1 demonstrates the composite transistor according to the presentdisclosure. To be more specific, the composite transistor is that of thefirst structure of the present disclosure. The composite transistor ofExample 1 may constitute a complementary transistor and an invertercircuit.

FIGS. 1A to 1C are conceptual diagrams depicting the compositetransistor of Example 1, FIGS. 2A and 2B are schematic diagramsdepicting the arrangement of the constituents of the inverter circuitconstituted of the composite transistor of Example 1, and FIG. 2C is aschematic diagram depicting the equivalent circuit of the invertercircuit, which is configured by the composite transistor of Example 1,with employing the symbols for FET for convenience sake. FIG. 3 is aschematic partly cutaway sectional view depicting the compositetransistor of Example 1. FIGS. 4A to 4C are conceptual diagramsdepicting the positional relation among the first active region, thesecond active region, and the control electrode in the compositetransistor of Example 1. FIGS. 5A to 5C are conceptual partly cutawaydiagrams each depicting the composite transistor of Example 1.Incidentally, FIG. 1A depicts that the first transistor is conductive(on) and the second transistor is non-conductive (off). FIG. 1B depictsthat the state of the first transistor transitions from conductive (on)to non-conductive (off) and that the state of the second transistortransitions from non-conductive (off) to conductive (on). FIG. 1Cdepicts that the first transistor is non-conductive (off) and the secondtransistor is conductive (on). In practice, FIGS. 2A and 2B overlap witheach other.

The composite transistors of Example 1 and Examples 2 and 3 (to bementioned later) are constructed as follows. A first active region 11,11′, 11″, a second active region 12, 12′, 12″, and a control electrode60 overlap with one another. The composite transistor includes a firstelectrode 61, a first electrode 61, and a third electrode 63. Aninsulation layer 71 is interposed between the control electrode 60 andthe first active region 11, 11′, 11″ or the second active region 12,12′, 12″ adjacent thereto. (The first active region 11, 11′, 11″ isdepicted.) The control electrode 60 includes TiN; the first electrode61, a second electrode 62, and the third electrode 63 include platinum(Pt); and the insulation layer 71 includes hafnium oxide (HfO₂), 1 nmthick.

Then, the composite transistor is additionally constructed as follows.First A extending part 111, 211, 311 extends from one end of the firstactive region 11, 11′, 11″; First B extending part 121, 221, 321 extendsfrom the other end of the first active region 11, 11′, 11″; Second Aextending part 131, 231, 331 extends from one end of the second activeregion 12, 12′, 12″; and Second B extending part 141, 241, 341 extendsfrom the other end of the second active region 12, 12′, 12″. The firstelectrode 61 is connected to the first A extending part 111, 211, 311;the second electrode 62 is connected to the second A extending part 131,231, 331; the third electrode 63 is connected to the first B extendingpart 121, 221, 321 and the second B extending part 141, 241, 341. Afirst transistor TR₁ includes the control electrode 60, the first activeregion 11, 11′, 11″, the first A extending part 111, 211, 311, and thefirst B extending part 121, 221, 321; and a second transistor TR₂includes the control electrode 60, the second active region 12, 12′,12″, the second A extending part 131, 221, 331, and the second Bextending part 141, 241, 341.

The composite transistors of Example 1 and Examples 2 and 3 (to bementioned later) function in the following manner. When the firstelectrode 61 is given a higher voltage than that which is applied to asecond electrode 62 and the control electrode 60 is given a firstvoltage V₁ (=0 volt), the first transistor TR₁ becomes conductive andthe second transistor TR₂ becomes non-conductive. When the controlelectrode 60 is given a second voltage V₂ (=V_(dd)>0 volt) higher than afirst voltage V₁ (=0 volt), the second transistor TR₂ becomes conductiveand the first transistor TR₁ becomes non-conductive. Incidentally, thevoltage applied to the first electrode 61 is designated as V₂ (=V_(dd)),and the voltage applied to the second electrode 62 is designated as V₁(=0<V₂=Vdd). In FIGS. 1A to 1C, FIGS. 7A to 7C, and FIGS. 9A to 9C, thevoltage applied to the control electrode 60 is designated as V_(CE) andthe voltage applied to a third electrode 63 is designated as V₃.

The composite transistors of Example 1 and Examples 2 and 3 (to bementioned later) have the first active region 11, 11′, 11″ and thesecond active region 12, 12′, 12″ which include a two-dimensionalmaterial or graphene.

The composite transistor according to Example 1 is the compositetransistor including the first structure of the present disclosure. Thecomposite transistor has the overlapping region in which a first activeregion 11 includes a first A active region 110 and a first B activeregion 120 overlapping with the first A active region 110, and a first Aextending part 111 extends from the first A active region 110 and afirst B extending part 121 extends from the first B active region 120.The composite transistor also has the overlapping region in which asecond active region 12 includes a second A active region 130 and asecond B active region 140 overlapping with the second A active region130, and a second A extending part 131 extends from the second A activeregion 130 and a second B extending part 141 extends from the second Bactive region 140.

The first A active region 110 differs from the first B active region 120in energy values as defined below.

E_(V-1A)<E_(V-1B)E_(C-1A)<E_(C-1B)where E_(V-1A) denotes the energy value at the upper end of the valenceband of the first A active region 110;

E_(C-1A) denotes the energy value at the lower end of the conductionband of the first A active region 110;

E_(V-1B) denotes the energy value at the upper end of the valence bandof the first B active region 120; and

E_(C-1B) denotes the energy value at the lower end of the conductionband of the first B active region 120. (See FIG. 25A.) Also, the secondA active region 130 differs from the second B active region 140 inenergy values as defined below.

E_(V-2A)>E_(V-2B)E_(C-2A)>E_(C-2B)where E_(V-2A) denotes the energy value at the upper end of the valenceband of the second A active region 130;

E_(C-2A) denotes the energy value at the lower end of the conductionband of the second A active region 130;

E_(V-2B) denotes the energy value at the upper end of the valence bandof the second B active region 140; and

E_(C-2B) denotes the energy value at the lower end of the conductionband of the second B active region 140. (See FIG. 25C.)

The first A active region 110 containing the first A extending part 111is an n-type active region, which concretely includes WTe₂, 1 nm thick.The first B active region 120 (containing the first B extending part121) is a p-type active region, which concretely includes MoS₂, 1 nmthick. The second A active region 130 (containing the second A extendingpart 131) is a p-type active region, which concretely includes MoS₂, 1nm thick. The second B active region 140 (containing the second Bextending part 141) is an n-type active region, which concretelyincludes WTe₂, 1 nm thick. These materials and thicknesses are merelyexemplary. The first A extending part 111 and the first B extending part121 extend in the same direction as the second A extending part 131 andthe second B extending part 141.

In the illustrated example, the second active region 12, the firstactive region 11, and the control electrode 60 are overlapped with oneanother in the order mentioned; however, overlapping may be made in theorder of the first active region 11, the second active region 12, andthe control electrode 60. The first A active region 110 and the first Bactive region 120 overlap with each other such that the first B activeregion 120 is close to the control electrode; however, this may bechanged such that the first A active region 110 is close to the controlelectrode. Also, the second A active region 130 and the second B activeregion 140 overlap with each other such that the second B active region140 is close to the control electrode; however, this may be changed suchthat the second A active region 130 is close to the control electrode.The composite transistor is formed on a silicon semiconductor substrate70 coated with an insulation film (not depicted).

The first active region 11 and the second active region 12 are separatedfrom each other by a second insulation layer 72 of SiO₂, 5 nm thick.Also, the first A active region 110 and the first B active region 120are separated from each other by a first interlayer insulation layer 73of HfO₂, 1 nm thick, which corresponds to the first boundary region. Thesecond A active region 130 and the second B active region 140 areseparated from each other by a second interlayer insulation layer 74 ofHfO₂, 1 nm thick, which corresponds to the second boundary region.

The composite transistor of Example 1 has the first transistor TR₁ andthe second transistor TR₂ which function in the way explained above withreference to FIGS. 25A to 25D.

The first active region 11 and the control electrode 60 overlap witheach other in the overlapping region such that the first active region11 may have its orthogonal projection image which is surrounded by thatof the control electrode 60 (see FIG. 4A), or which coincides with thatof the control electrode 60 (see FIG. 4B), or which projects from thatof the control electrode 60 (see FIG. 4C). Likewise, it has theoverlapping region in which the second active region 12 and the controlelectrode 60 overlap each other such that the second active region 12may have its orthogonal projection image which is surrounded by that ofthe control electrode 60 (see FIG. 4A), or which coincides with that ofthe control electrode 60 (see FIG. 4B), or which projects from that ofthe control electrode 60 (see FIG. 4C). It is desirable from thestandpoint of the control electrode 60 generating a uniform electricfield that the first active region 11 and the second active region 12give the orthogonal projection image which is preferably surrounded bythat of the control electrode 60.

Also, the first A active region 110 which constitutes the first activeregion 11 and the first B active region 120 overlap with each other inthe overlapping region such that the overlapping region of the first Aactive region 110 and the first B active region 120 may have itsorthogonal projection image which is surrounded by that of the controlelectrode 60 (see FIG. 5A), or which coincides with that of the controlelectrode 60 (see FIG. 5B), or which projects from that of the controlelectrode 60 (see FIG. 5C). Likewise, it has the overlapping region inwhich the second A active region 130 which constitutes the second activeregion 12 and the second B active region 140 overlap each other suchthat the second A active region 130 and the second B active region 140may have the orthogonal projection image which is surrounded by that ofthe control electrode 60 (see FIG. 5A), or which coincides with that ofthe control electrode 60 (see FIG. 5B), or which projects from that ofthe control electrode 60 (see FIG. 5C).

The composite transistor of Example 1 is produced by the method which isbriefly described below with reference to FIGS. 24A to 24D.

First, the silicon semiconductor substrate 70 with an insulation filmformed thereon (not depicted) is coated with MoS₂ by CVD method. Thecoating on the substrate undergoes patterning to desired form to givethe second A active region 130 containing the second A extending part131. (See FIG. 24A.) The patterning may be accomplished by oxygen plasmaetching.

The substrate is entirely coated with the second interlayer insulationlayer 74, which, after coating with WTe₂ by CVD method, undergoespatterning to desired form. Thus, there is obtained the second B activeregion 140 containing the second B extending part 141. (See FIG. 24B.)

The substrate is entirely coated with the second insulation layer 72,which, after coating with WTe₂ by CVD method, undergoes patterning todesired form. Thus, there is obtained the first A active region 110containing the first A extending part 111. (See FIG. 24C.)

The entire surface is covered with the first interlayer insulation layer73, which is subsequently coated with MoS₂ by CVD method, followed bypatterning to desired form. Thus, there is obtained the first B activeregion 120 containing the first B extending part 121. (See FIG. 24D.)

The entire surface is covered with the insulation layer 71, which issubsequently topped with the control electrode 60. Then, the entiresurface is covered with an upper interlayer insulation layer 75, whichis subsequently fabricated to form openings above the first A extendingpart 111, the second A extending part 131, the first B extending part121, and the second B extending part 141. Then, these openings arefilled with a conductive material so that the first electrode 61, thesecond electrode 62, and the third electrode 63 are formed over the topof the upper interlayer insulation layer 75. (See FIG. 3.)

The composite transistor of Example 1, in which the first transistor andthe second transistor include the control electrode, the first activeregion, and the second active region overlap with one another, ischaracterized in that the first transistor and the second transistor arecontrolled by the electric field (or vertical electric field) generatedby one control electrode. This contributes to a higher density and asimpler wiring which leads to a reduced parasitic capacity (and hence areduced power consumption). Another advantage is a considerable overallthickness reduction in the first active region and the second activeregion, and this permits the planer process in the past to be appliedowing to a reduced step and also permits the two transistors to beconnected easily by contact connection.

The composite transistor of Example 1 is depicted in FIG. 6 (right side)which is a schematic plan view, and the CMOS circuit in the past isdepicted in FIG. 6 (left side) which is a schematic plan view.Incidentally, the hatched part in FIG. 6 indicates the control electrode(gate part). It is noted from the plan view that the CMOS circuit in thepast is as long as “9F” in the Y direction, with “F” denoting theminimum fabrication size. By contrast, the composite transistor ofExample 1 only needs a length of “4F” in the Y direction. Similarly, theCMOS circuit in the past takes a length of “1” in the X direction,whereas the composite transistor of Example 1 takes a length of 1.5.This means that the composite transistor of Example 1 has 0.66 times aslarge footprint and 1.5 times as high gate density as the CMOS circuitin the past, as calculated below.

(4/9)×1.5=0.66 and 1/0.66=1.5

The result is a higher degree of integration and a uniformity oftransistor characteristics because of the absence of scaling.

Example 2

Example 2 is concerned with a modification of the composite transistorof Example 1 or the composite transistor including the second structurewhich is of the present disclosure. The composite transistor of Example2 is depicted in FIGS. 7A, 7B, and 7C, which are conceptual diagrams.The composite transistor of Example 2 is also depicted in FIG. 8A, whichis a schematic partly cutaway sectional view. Incidentally, FIG. 7Adepicts that the first transistor is conductive (on) and the secondtransistor is non-conductive (off). FIG. 7B depicts that the state ofthe first transistor transitions from conductive (on) to non-conductive(off) and that the state of the second transistor transitions fromnon-conductive (off) to conductive (on). FIG. 7C depicts that the firsttransistor is non-conductive (off) and the second transistor isconductive (on).

The composite transistor of Example 2 including the second structureaccording to the present disclosure has the overlapping region in whichthe first active region 11′ includes a first A active region 210 and afirst B active region 220 which is positioned on the same virtual planeas the first A active region 210 and which faces the first A activeregion 210, a first A extending part 211 extends from the first A activeregion 210, a first B extending part 221 extends from the first B activeregion 220, and it also has the overlapping region in which the secondactive region 12′ includes a second A active region 230 and a second Bactive region 240 which is positioned on the same virtual plane as thesecond A active region 230 and which faces the second A active region230, a second A extending part 231 extends from the second A activeregion 230, a second B extending part 241 extends from the second Bactive region 240.

The first A active region 210 differs from the first B active region 220in energy values as defined below.

E_(V-1A)<E_(V-1B)E_(C-1A)<E_(C-1B)where E_(V-1A) denotes the energy value at the upper end of the valenceband of the first A active region 210;

E_(C-1A) denotes the energy value at the lower end of the conductionband of the first A active region 210;

E_(V-1B) denotes the energy value at the upper end of the valence bandof the first B active region 220; and

E_(C-1B) denotes the energy value at the lower end of the conductionband of the first B active region 220.

Also, the second A active region 230 differs from the second B activeregion 240 in energy values as defined below.

E_(V-2A)>E_(V-2B)E_(C-2A)>E_(C-2B)where E_(V-2A) denotes the energy value at the upper end of the valenceband of the second A active region 230;

E_(C-2A) denotes the energy value at the lower end of the conductionband of the second A active region 230;

E_(V-2B) denotes the energy value at the upper end of the valence bandof the second B active region 240; and

E_(C-2B) denotes the energy value at the lower end of the conductionband of the second B active region 240.

The composite transistor of Example 2 has the energy values definedbelow when it is non-conductive.

E_(C-1B)>E_(C-1A)>E_(V-1B)>E_(V-1A), andE_(C-2A)>E_(C-2B)>E_(V-2A)>E_(V-2B)

It also has the energy values defined below when it is conductive.

E_(C-1B)>E_(V-1B)>E_(C-1A)>E_(V-1A), andE_(C-2A)>E_(V-2A)>E_(C-2B)>E_(V-2B)

The first active region 11′ and the second active region 12′ areseparate from each other, with the second insulation layer 72 interposedbetween them. Also, the first A active region 210 and the first B activeregion 220 are separate from each other, with a first boundary region212 interposed between them. The second A active region 230 and thesecond B active region 240 are separate from each other with a secondboundary region 232 interposed between them. Incidentally, as depictedin FIG. 8B, the first A active region 210 and the first B active region220 may be in contact with each other, and the second A active region230 and the second B active region 240 may not be in contact with eachother.

The first A active region 210 (containing the first A extending part211) is an n-type active region, which concretely includes WTe₂, 3 nmthick. The first B active region 220 (containing the first B extendingpart 221) is a p-type active region, which concretely includes WTe₂, 3nm thick. The second A active region 230 (containing the second Aextending part 231) is a p-type active region, which concretely includesMoS₂, 3 nm thick. The second B active region 240 (containing the secondB extending part 241) is an n-type active region, which concretelyincludes MoS₂, 3 nm thick. The first boundary region 212 is an intrinsicactive region, which concretely includes WTe₂, 3 nm thick. The secondboundary region 232 is also an intrinsic active region which concretelyincludes MoS₂, 3 nm thick.

The composite transistor of Example 2 is produced by the method which isbriefly described below.

First, the silicon semiconductor substrate 70 with an insulation filmformed thereon is coated with MoS₂ by CVD method. The coating on thesubstrate undergoes patterning to desired form to give the second Aactive region 230 (containing the second A extending part 231), thesecond B active region 240 (containing the second B extending part 241)and the region which becomes the second boundary region 232. Chemicaldoping is performed to form the second A active region 230 (containingthe second A extending part 231) which is a p-type active region, andalso to form the second B active region 240 (containing the second Bextending part 241) which is an n-type active region. Incidentally, thechemical doping should preferably be performed through a mask layer forprotection from unnecessary doping.

Next, the entire surface is coated with the second insulation layer 72,which is subsequently coated with WTe₂ by CVD method. Coating layerundergoes patterning to desired form to obtain the first A active region210 (containing the first A extending part 211), the first B activeregion 220 (containing the first B extending part 221), and the regionfor the first boundary region 212. Chemical doping is performed to formthe first A active region 210 as an n-type active region (containing thefirst A extending region 211) and the first B active region 220 as ap-type active region (containing the first B extending region 221).

Finally, the entire surface is coated sequentially with the insulationlayer 71 and the control electrode 60, and the entire surface is furthercoated with the upper interlayer insulation layer 75, in which openingsare formed at the positions above the first A extending part 211, thesecond A extending part 231, the first B extending part 221, and thesecond B extending part 241. These openings are filled with a conductivematerial to form the first electrode 61, the second electrode 62, andthe third electrode 63 on the top of the upper interlayer insulationlayer 75.

Example 3

Example 3 is also concerned with a modification of the compositetransistor of Example 1 or the composite transistor including the thirdstructure of the present disclosure. The composite transistor of Example3 is depicted in FIGS. 9A to 9C, which are conceptual diagrams. Thecomposite transistor of Example 3 is also depicted in FIG. 10, which isa schematic partly cutaway sectional view. Incidentally, FIG. 9A depictsa state in which the first transistor is conductive (on) and the secondtransistor is non-conductive (off). FIG. 9B depicts a state in which thefirst transistor transitions from conductive (on) to non-conductive(off) and the second transistor transitions from non-conductive (off) toconductive (on). FIG. 9C depicts a state in which the first transistoris non-conductive (off) and the second transistor is conductive (on).

The composite transistor according to Example 3 including the thirdstructure of the present disclosure has an overlapping region in whichthe first active region 11″ includes a first channel forming region 310,the first A extending part 311 extends from one end of the first channelforming region 310, the first B extending part 321 extends from theother end of the first channel forming region 310, and also has anoverlapping region in which the second active region 12″ includes asecond channel forming region 330, the second A extending part 311extends from one end of the second channel forming region 330, and thesecond B extending part 341 extends from the other end of the secondchannel forming region 330.

When the control electrode 60 is given the first voltage V₁, the firsttransistor TR₁ becomes conductive and the second transistor TR₂ becomesnon-conductive, and when the control electrode 60 is given the secondvoltage V₂ (>V₁) higher than the first voltage V₁, the second transistorTR₂ becomes conductive and the first transistor TR₁ becomesnon-conductive. Thus, the composite transistor of Example 3 functionsbasically in the same way as the field-effect transistor in the past.

The composite transistor of Example 3 is constructed such that the firstactive region 11″ and the second active region 12″ are separated fromeach other by the second insulation layer 72. In the compositetransistor of Example 3, the first active region 11″ (the first channelforming region 310) is a 3-nm thick layer of WTe₂, and the second activeregion 12″ (the second channel forming region 330) is a 3-nm thick layerof MoS₂. Each of the first A extending part 311 and the first Bextending part 321 is a 3-nm thick layer of WTe₂ doped with a p-typeimpurity, and each of the second A extending part 331 and the second Bextending part 341 is a 3-nm thick layer of MoS₂ doped with an n-typeimpurity.

The composite transistor of Example 3 is produced by a method which isbriefly described below.

That is, the silicon semiconductor substrate 70 with an insulation filmformed thereon is coated with MoS₂ by the CVD method. The coating on thesubstrate undergoes patterning into the desired shape to form the secondchannel forming region 330 and the region which becomes the second Aextending part 331 and the second B extending part 341. The second Aextending part 331 and the second B extending part 341 (containing ann-type impurity) are formed by an ion injection method. Incidentally,the ion injection method should be performed through a mask layer forprotection of an area from unnecessary ion injection.

Next, the entire surface is coated with the second insulation layer 72,which is subsequently coated with WTe₂ by CVD method. Coating layerundergoes patterning into the desired shape to form the first channelforming region 310 and the region which becomes the first A extendingpart 311 and the first B extending part 321. Then, the first A extendingpart 311 and the first B extending part 321 (containing a p-typeimpurity) are formed by the ion injection method.

Finally, the entire surface is coated sequentially with the insulationlayer 71 and the control electrode 60, and the entire surface is furthercoated with the upper interlayer insulation layer 75, in which openingsare formed at the positions above the first A extending part 311, thesecond A extending part 331, the first B extending part 321, and thesecond B extending part 341. These openings are filled with a conductivematerial to form the first electrode 61, the second electrode 62, andthe third electrode 63 on the top of the upper interlayer insulationlayer 75.

Example 4

Example 4 is a modification of Examples 1 to 3. It is concerned with thelogic circuit including the composite transistors according to Examples1 to 3.

FIG. 11A is an equivalent circuit diagram of the NAND circuit which isformed on the basis of the composite transistors of Examples 1 to 3.FIGS. 11B and 11C are schematic diagrams depicting the arrangement ofthe constituents of the NAND circuit which is configured on the basis ofthe composite transistor of Example 1. Incidentally, FIGS. 11B and 11Coverlap with each other in the actual structure. FIGS. 12A to 12C areconceptual partly cutaway sectional views each depicting the NANDcircuit which is formed on the basis of the composite transistoraccording to Examples 1 to 3. Incidentally, the equivalent circuitdiagram depicted in FIG. 11A is based on the composite transistor ofExample 1.

The NAND circuit includes four transistors Tr₁, Tr₂, Tr₃, and Tr₄. Thefirst and second transistors TR₁ and Tr₂ include the compositetransistor of the present disclosure. In other words, the first andsecond transistors Tr₁ and Tr₂ correspond to the first and secondtransistors TR₁ and TR₂, respectively.

The first transistor TR₁ (Tr₁) includes a control electrode 60 ₁, afirst active region 11 ₁, 11′₁, 11″₁, a first A extending part 111 ₁,211 ₁, 311 ₁, and a first B extending part 121 ₁, 221 ₁, 321 ₁. Also,the second transistor TR₂ (Tr₂) includes the control electrode 60 ₁, asecond active region 12 ₂, 12′₂, 12″₂, a second A extending part 131 ₂,231 ₂, 331 ₂, and a second B extending part 141 ₂, 241 ₂, 341 ₂.

Moreover, a third transistor Tri constituting the NAND circuitsubstantially includes the first transistor TR₁. To be concrete, itincludes a control electrode 60 ₂, a first active region 11 ₃, 11′₃,11″₃, a first A extending part 111 ₃, 211 ₃, 311 ₃, and a first Bextending part 121 ₃, 221 ₃, 321 ₃. Also, a fourth transistor Tr₄constituting the NAND circuit substantially includes the secondtransistor TR₂. To be concrete, it includes the control electrode 60 ₂,a second active region 12 ₄, 12′₄, 12″₄, a second A extending part 131₄, 231 ₄, 331 ₄, and a second B extending part 141 ₄, 241 ₄, 341 ₄.Incidentally, the second A extending part 131 ₂ and the second Bextending part 141 ₄ connect to each other through a connecting part 64.

FIG. 13 is a schematic diagram depicting the NAND circuit formed on thebasis of the composite transistor according to Example 1, with itsactive regions, etc. being cut along virtual planes at four levels.Incidentally, FIGS. 13, 14A, 14B, 17, 18A, 18B, 23A, and 23B also depictthe control electrode.

Here, FIG. 13 (upper part) depicts a first B active region 120 ₁, 120 ₃and the first B extending part 121 ₁, 121 ₃, which are positioned at thefirst level closest to the level of the control electrode and alsodepicts a first A active region 110 ₁, 110 ₃ and the first A extendingpart 111 ₁, 111 ₃, which are positioned at the second level below thefirst level. Also, FIG. 13 (lower part) depicts the second B activeregion 140 ₂, 140 ₄ and the second B extending part 141 ₂, 141 ₄, whichare positioned at the third level below the second level and alsodepicts the second A active region 130 ₂, 130 ₄ and the second Aextending part 131 ₂, 131 ₄, which are positioned at the fourth levelwhich is the lowest level below the third level.

FIG. 14A is a schematic diagram depicting the NAND circuit formed on thebasis of the composite transistor according to Example 2, with itsactive regions, etc. being cut along virtual planes at two levels. FIG.14A (upper part) depicts a first A active region 210 ₁, 210 ₃, a first Bactive region 220 ₁, 220 ₃, a first A extending part 211A₁, 211A₃, and afirst B extending part 221B₁, 221B₃, which are positioned at the firstlevel closest to the level of the control electrode. Also, FIG. 14A(lower part) depicts a second A active region 230 ₂, 230 ₄, a second Bactive region 240 ₂, 240 ₄, a second A extending part 231A₂, 231A₄, anda second B extending part 241B₂, 241B₄, which are positioned at thesecond level below the first level.

In addition, FIG. 14B is a schematic diagram depicting the NAND circuitformed on the basis of the composite transistor according to Example 3,with its active regions, etc. being cut along virtual planes at twolevels. FIG. 14B (upper part) depicts a first channel forming region 310₁, 310 ₃, a first A extending part 311A₁, 311A₃, and a first B extendingpart 321B₁, 321B₃, which are positioned at the first level closest tothe level of the control electrode. Also, FIG. 14B (lower part) depictsa second channel forming region 330 ₂, 330 ₄, a second A extending part331A₂, 331A₄, and a second B extending part 341B₂, 341B₄, which arepositioned at the second level below the first level.

FIG. 15A is an equivalent circuit diagram of the NOR circuit which isformed on the basis of the composite transistors of Examples 1 to 3.FIGS. 15B and 15C are schematic diagrams depicting the arrangement ofthe constituents of the NOR circuit which is formed on the basis of thecomposite transistor of Example 1. Incidentally, FIGS. 15B and 15Coverlap with each other in the actual structure. FIGS. 16A to 16C areconceptual partly cutaway sectional views each depicting the NOR circuitwhich is formed on the basis of the composite transistor according toExamples 1 to 3. Incidentally, the equivalent circuit diagram depictedin FIG. 15A is based on the composite transistor of Example 1.

The NOR circuit includes four transistors Tr₁, Tr₂, Tr₃, and Tr₄. Thefirst and second transistors Tr₁ and Tr₂ include the compositetransistor of the present disclosure. In other words, the first andsecond transistors Tr₁ and Tr₂ correspond to the first and secondtransistors TR₁ and TR₂, respectively.

The first transistor TR₁ (Tr₁) includes the control electrode 60 ₁, thefirst active region 11 ₁, 11′₁, 11″₁, the first A extending part 111 ₁,211 ₁, 311 ₁, and the first B extending part 121 ₁, 221 ₁, 321 ₁. Also,the second transistor TR₂ (Tr₂) includes the control electrode 60 ₁, thesecond active region 12 ₂, 12′₂, 12″₂, the second A extending part 131₂, 231 ₂, 331 ₂, and the second B extending part 141 ₂, 241 ₂, 341 ₂.

Moreover, the third transistor Tr₃ constituting the NOR circuitsubstantially includes the first transistor TR₁. To be concrete, itincludes the control electrode 60 ₂, the first active region 11 ₃, 11′₃,11″₃, the first A extending part 111 ₃, 211 ₃, 311 ₃, and the first Bextending part 121 ₃, 221 ₃, 321 ₃. Also, the fourth transistor Tr₄constituting the NOR circuit substantially includes the secondtransistor TR₂. To be concrete, it includes the control electrode 60 ₂,the second active region 12 ₄, 12′₄, 12″₄, the second A extending part131 ₄, 231 ₄, 331 ₄, and the second B extending part 141 ₄, 241 ₄, 341₄.

FIG. 17 is a schematic diagram depicting the NOR circuit formed on thebasis of the composite transistor according to Example 1, with itsactive regions, etc. being cut along virtual planes at four levels.

Here, FIG. 17 (upper part) depicts the first A active region 110 ₁, thefirst B active region 120 ₃, the first A extending part 111 ₁, and thefirst B extending part 121 ₃, which are positioned at the first levelclosest to the level of the control electrode, and also depicts thefirst B active region 120 ₁, the first A active region 110 ₃, the firstB extending part 121 ₁, and the first A extending part 113 ₃, which arepositioned at the second level below the first level. Also, FIG. 17(lower part) depicts the second B active region 140 ₂, 140 ₄ and thesecond B extending part 141 ₂, 141 ₄, which are positioned at the thirdlevel below the second level and also depicts the second A active region130 ₂, 130 ₄ and the second A extending part 131 ₂ 131 ₄, which arepositioned at the fourth level which is the lowest level below the thirdlevel.

In addition, FIG. 18A is a schematic diagram depicting the NOR circuitformed on the basis of the composite transistor according to Example 2,with its active regions, etc. being cut along virtual planes at twolevels. FIG. 18A (upper part) depicts the first A active region 210 ₁,210 ₃, the first A extending part 211A₁, 211A₃, and the first Bextending part 221B₁, 221B₃, which are positioned at the first levelclosest to the level of the control electrode. Also, FIG. 18A (lowerpart) depicts the second A active region 230 ₂, 230 ₄, the second Aextending part 231A₂, 231A₄, and the second B extending part 241B₂,241B₄, which are positioned at the second level below the first level.

In addition, FIG. 18B is a schematic diagram depicting the NOR circuitformed on the basis of the composite transistor according to Example 3,with its active regions, etc. being cut along virtual planes at twolevels. FIG. 18B (upper part) depicts the first channel forming region310 ₁, 310 ₃, the first A extending part 311A₁, 311A₃, and the first Bextending part 321B₁, 321B₃, which are positioned at the first levelclosest to the level of the control electrode. Also, FIG. 18B (lowerpart) depicts the second channel forming region 330 ₂, 330 ₄, the secondA extending part 331A₂, 331A₄, and the second B extending part 341B₂,341B₄, which are positioned at the second level below the first level.

FIG. 19 is an equivalent circuit diagram of the SRAM circuit includingeight transistors formed on the basis of the composite transistorsaccording to Example 1, Example 2, and Example 3. FIGS. 20A and 20B areschematic diagrams depicting the arrangement of the constituents of theSRAM circuit which is formed on the basis of the composite transistor ofExample 1. Incidentally, in the actual structure, the constituents ofthe SRAM circuit depicted in FIG. 20A (upper part) overlap with theconstituents of the SRAM circuit depicted in FIG. 20B (upper part).Also, in the actual structure, the constituents of the SRAM circuitdepicted in FIG. 20A (middle part) overlap with the constituents of theSRAM circuit depicted in FIG. 20B (lower part). In addition, FIGS. 21Aand 21B are conceptual partly cutaway sectional views each depicting theSRAM circuit which is formed on the basis of the composite transistoraccording to Example 1. Moreover, FIGS. 22A and 22B are conceptualpartly cutaway sectional views each depicting the SRAM circuit which isformed on the basis of the composite transistor according to Example 2.FIGS. 22C and 22D are conceptual partly cutaway sectional views eachdepicting the SRAM circuit which is formed on the basis of the compositetransistor according to Example 3. Incidentally, the equivalent circuitdiagram depicted in FIG. 19 is based on the composite transistor ofExample 1.

The SRAM circuit according to Example 4 includes eight transistors Tr₁,Tr₂, Tr₃, Tr₄, Tr₅, Tr₆, Tr₇, and Tr₈. The structure of the SRAM circuitis known well, and hence its detailed description is omitted here.

Here, the transistor Tr₃ has its one end connected to a writing bit lineWBL through a connecting part 65′, and the transistor Tr₃ has itscontrol electrode 60 ₂′ connected to a writing word line WWL. Also, thetransistor Tr₆ has its one end connected to a writing bit line WBLXthrough a connecting part 65, and the transistor Tr₆ has its controlelectrode 60 ₂ connected to the writing word line WWL. Moreover, thetransistor Tr₇ has its one end connected to a reading bit line RBLthrough a connecting part 66, and the transistor Tr₇ has its controlelectrode 60 ₄ connected to a reading word line RWL. Also, thetransistor Tr₈ has its control electrode 60 ₃ connected to the thirdelectrode 63, the transistor Tr₈ has its one end connected to the otherend of the transistor Tr₇, and the transistor Tr₈ has its other endgrounded through a connecting part 67.

The illustrated circuit contains the fourth transistor Tr₄ and the fifthtransistor Tr₅ which constitute the composite transistor disclosedherein. In other words, the fourth transistor Tr₄ corresponds to thefirst transistor TR₁ and the fifth transistor Tr₅ corresponds to thesecond transistor TR₂. Moreover, the first transistor Tr₁ and the secondtransistor Tr₂ are identical in configuration and structure with thecomposite transistor of the present disclosure except that they lack thethird electrode. In other words, the first transistor Tr₁ corresponds tothe first transistor TR₁ and the second transistor Tr₂ corresponds tothe second transistor TR₂. The first transistor Tr₁ includes a controlelectrode 60 ₁′ and is connected to the first electrode 61 and aconnecting part A. The second transistor Tr₂ includes the controlelectrode 60 ₁′ and is connected to the second electrode 62 and theconnecting part A. The third transistor Tr₃ is provided with the controlelectrode 60 ₂′ and is connected to the connecting part 65′ and theconnecting part A.

The following description covers the fourth transistor Tr₄, the fifthtransistor Tr₅, the sixth transistor Tr₆, the seventh transistor Tr₇,and the eighth transistor Tr₈. However, it does not cover the firsttransistor Tr₁, the second transistor Tr₂, and the third transistor Tr₃.

The first transistor TR₁ (the fourth transistor Tr₁) includes thecontrol electrode 60 ₁, the first active region 11 ₁, 11′₁, 11″₁, afirst A extending part 111 ₄, 211 ₄, 311 ₄, and a first B extending part121 ₄, 221 ₄, 321 ₄. Also, the second transistor TR₂ (the fifthtransistor Tr₅) includes the control electrode 60 ₁, a second activeregion 12 ₅, 12′₅, 12″₅, a first A extending part 131 ₅, 231 ₅, 331 ₅,and a second B extending part 141 ₅, 241 ₅, 341 ₅.

In addition, the sixth transistor Tr₆ substantially includes the secondtransistor TR₂. To be concrete, it includes the control electrode 60 ₂,a first active region 12 ₆, 12′₆, 12″₆, a second A extending part 131 ₆,231 ₆, 331 ₆, and a second B extending part 141 ₆, 241 ₆, 341 ₆.

The seventh transistor Tr₇ also substantially includes the secondtransistor TR₂. To be concrete, it includes the control electrode 60 ₄,a first active region 12 ₇, 12′₇, 12″₇, a second A extending part 131 ₇,231 ₇, 331 ₇, and a second B extending part 141 ₇, 241 ₇, 341 ₇.

The eighth transistor Tr₈ also substantially includes the secondtransistor TR₂. To be concrete, it includes the control electrode 60 ₄,a first active region 12 ₈, 12′₈, 12″₈, a second A extending part 131 ₈,231 ₈, 331 ₈, and a second B extending part 141 ₈, 241 ₈, 341 ₈. Thesecond B extending part 141 ₈ as a constituent of the eighth transistorTr₈ is connected to the second A extending part 131 ₇ as a constituentof the seventh transistor Tr₇ through a connecting part 68.

FIGS. 23A and 23B are schematic diagrams depicting the SRAM circuitformed on the basis of the composite transistor according to Example 1,with its active regions, etc. being cut along virtual planes at fourlevels and one level. FIG. 23A (upper part) depicts a first B activeregion 120 ₄ and the first B extending part 121 ₄, which are positionedat the first level closest to the level of the control electrode, and italso depicts a first A active region 110 ₄ and the first A extendingpart 111 ₄, which are positioned at the second level below the firstlevel. Also, FIG. 23A (lower part) depicts a second B active region 140₅, 140 ₆ and the second B extending part 141 ₅ and 141 ₆, which arepositioned at the third level below the second level, and it alsodepicts a second A active region 130 ₅, 130 ₆, and the second Aextending part 131 ₅, 131 ₆, which are positioned at the forth level(lowermost level) below the third level.

In addition, FIG. 23B depicts a second B active region 140 ₇, 140 ₈, andthe second B extending part 141 ₇, 141 ₈, which are positioned at thefirst level closest to the control electrode, and it also depicts asecond A active region 130 ₇, 130 ₈ and the second A extending part 131₇, 131 ₈, which are positioned at the second level below the firstlevel.

The composite transistor of the present disclosure has been describedabove on the basis of the preferred examples. However, the compositetransistor of the present disclosure can be variously modified withoutbeing restricted to the illustrated ones in its structure, materials,and manufacturing method. In addition, various application examples ofthe composite transistor of the present disclosure described in theexamples are merely examples and can be applied to various circuitsother than mentioned above.

What is disclosed herein may be embodied in the following manner.

[A01] <Composite Transistor>

A composite transistor including:

a first transistor including a control electrode, a first active region,a first A extending part, and a first B extending part; and

a second transistor including a control electrode, a second activeregion, a second A extending part, and a second B extending part,

in which the first active region, the second active region, and thecontrol electrode overlap with one another in an overlapping region,

each of the transistors has a first electrode, a second electrode, and athird electrode,

an insulation layer is provided between the control electrode and one ofthe first active region and the second active region both adjacent tothe control electrode,

each of the two transistors has the first A extending part that extendsfrom one end of the first active region, the first B extending part thatextends from other end of the first active region, the second Aextending part that extends from one end of the second active region,and the second B extending part that extends from other end of thesecond active region,

the first electrode connects to the first A extending part,

the second electrode connects to the second A extending part, and

the third electrode connects to the first B extending part and thesecond B extending part.

[A02]

The composite transistor as defined in [A01], in which the firsttransistor becomes conductive and the second transistor becomesnon-conductive when the first electrode is given a voltage higher than avoltage given to the second electrode and the control electrode is givena first voltage, and the second transistor becomes conductive and thefirst transistor becomes non-conductive when the control electrode isgiven a second voltage higher than the first voltage.

[A03]

The composite transistor as defined in [A01] or [A02], in which thefirst active region and the second active region include atwo-dimensional material or graphene.

[A04] <Composite Transistor of the First Structure>

The composite transistor as defined in any one of [A01] to [A03],

in which the first active region in the overlapping region includes afirst A active region and a first B active region overlapping with thefirst A active region,

the first A extending part extends from the first A active region,

the first B extending part extends from the first B active region,

the second active region in the overlapping region includes a second Aactive region and a second B active region overlapping with the second Aactive region,

the second A extending part extends from the second A active region,

the second B extending part extends from the second B active region,

an energy value E_(V-1A) at an upper end of a valence band and an energyvalue E_(C-1A) at a lower end of a conduction band of the first A activeregion are smaller than an energy value E_(V-1B) at an upper end of avalence band and an energy value E_(C-1B) at a lower end of a conductionband of the first B active region, respectively, and

an energy value E_(V-2A) at an upper end of a valence band and an energyvalue E_(C-2A) at a lower end of a conduction band of the second Aactive region are larger than an energy value E_(V-2B) at an upper endof a valence band and an energy value E_(C-2B) at a lower end of aconduction band of the second B active region, respectively.

[A05]

The composite transistor as defined in [A04], in which a secondinsulation layer is provided between the first active region and thesecond active region.

[A06]

The composite transistor as defined in [A05],

in which a first interlayer insulation layer is provided between thefirst A active region and the first B active region, and

a second interlayer insulation layer is provided between the second Aactive region and the second B active region.

[A07] <Composite Transistor of the Second Structure>

The composite transistor as defined in any one of [A01] to [A03],

in which the first active region in the overlapping region includes afirst A active region and a first B active region which is positioned onthe same virtual plane as the first A active region and which faces thefirst A active region,

the first A extending part extends from the first A active region,

the first B extending part extends from the first B active region,

the second active region in the overlapping region includes a second Aactive region and a second B active region which positions on the samevirtual plane as the second A active region and which faces the second Aactive region,

the second A extending part extends from the second A active region,

the second B extending part extends from the second B active region,

an energy value E_(V-1A) at an upper end of a valence band and an energyvalue E_(C-1A) at a lower end of a conduction band of the first A activeregion are smaller than an energy value E_(V-1B) at an upper end of avalence band and an energy value E_(C-1B) at a lower end of a conductionband of the first B active region, respectively, and

an energy value E_(V-2A) at an upper end of a valence band and an energyvalue E_(C-2A) at a lower end of a conduction band of the second Aactive region are larger than an energy value E_(V-2B) at an upper endof a valence band and an energy value E_(C-2B) at a lower end of aconduction band of the second B active region, respectively.

[A08]

The composite transistor as defined in [A07], in which a secondinsulation layer is provided between the first active region and thesecond active region.

[A09] <Composite Transistor of the Third Structure>

The composite transistor as defined in [A01],

in which the first active region in the overlapping region includes afirst channel forming region,

the first A extending part extends from one end of the first channelforming region,

the first B extending part extends from the other end of the firstchannel forming region,

the second active region in the overlapping region includes a secondchannel forming region,

the second A extending part extends from one end of the second channelforming region,

the second B extending part extends from other end of the second channelforming region,

the first transistor becomes conductive and the second transistorbecomes non-conductive when the control electrode is given a firstvoltage, and

the second transistor becomes conductive and the first transistorbecomes non-conductive when the control electrode is given a secondvoltage which is higher than the first voltage.

[A10]

The composite transistor as defined in [A09], in which a secondinsulation layer is provided between the first active region and thesecond active region.

[A11]

The composite transistor as defined in [A09] or [A10], in which thefirst active region and the second active region include atwo-dimensional material or graphene.

REFERENCE SIGNS LIST

11, 11′, 11″ . . . First active region

12, 12′, 12″ . . . Second active region

60, 60′ . . . Control electrode

61 . . . First electrode

62 . . . Second electrode

63 . . . Third electrode

64, 65, 65′, 66, 67, 68 . . . Connecting part

70 . . . Silicon semiconductor substrate

71 . . . Insulation layer

72 . . . Second insulation layer

73 . . . First interlayer insulation layer (first boundary region)

74 . . . Second interlayer insulation layer (second boundary region)

75 . . . Upper interlayer insulation layer

110, 210 . . . First A active region

120, 220 . . . First B active region

130, 230 . . . Second A active region

140, 240 . . . Second B active region

310 . . . First channel forming region

330 . . . Second channel forming region

111, 211, 311 . . . First A extending part

121, 221, 321 . . . First B extending part

131, 231, 331 . . . Second A extending part

141, 241, 341 . . . Second B extending part

212 . . . First boundary region

232 . . . Second boundary region

TR₁ . . . First transistor

TR₂ . . . Second transistor

What is claimed is:
 1. A composite transistor, comprising: a controlelectrode; a first electrode; a second electrode; a third electrode; afirst A extending part, wherein the first A extending part extends fromthe first electrode to a first A active region; a second A extendingpart, wherein the second A extending part extends from the secondelectrode to a second A active region; a first B extending part, whereinthe first B extending part extends from the third electrode to a first Bactive region; a second B extending part, wherein the second B extendingpart extends from the third electrode to a second B active region. 2.The composite transistor according to claim 1, wherein the controlelectrode, the first B active region, and the first A active region, andsecond B active region, and the second A active region are stacked withone another, with the first B active region between the controlelectrode and the first A active region, with the first A active regionbetween the first B active region and the second B active region, andwith the second B active region between the first A active region andthe second A active region.
 3. The composite transistor according toclaim 2, wherein an insulating layer is disposed between the controlelectrode and the first B active region.
 4. The composite transistoraccording to claim 1, wherein the first A active region and the first Bactive region are disposed on a first virtual plane, and wherein a firstboundary region disposed on the first virtual plane is interposedbetween the first A active region and the first B active region.
 5. Thecomposite transistor according to claim 4, wherein the second A activeregion and the second B active region are disposed on a second virtualplane, and wherein a second boundary region disposed on the secondvirtual plane is interposed between the second A active region and thesecond B active region.
 6. The composite transistor according to claim5, wherein the first boundary region is between the control electrodeand the second boundary region.
 7. The composite transistor according toclaim 6, wherein the first A active region and the first B active regionare in contact with each other, and wherein the second A active regionand the second B active region are not in contact with each other. 8.The composite transistor according to claim 1, wherein the firsttransistor becomes conductive and the second transistor becomesnon-conductive when the first electrode is given a voltage higher than avoltage given to the second electrode and the control electrode is givena first voltage, and the second transistor becomes conductive and thefirst transistor becomes non-conductive when the control electrode isgiven a second voltage higher than the first voltage.
 9. The compositetransistor according to claim 1, wherein the first active region and thesecond active region include a two-dimensional material or graphene. 10.The composite transistor of claim 1, wherein a second insulation layeris provided between the first active region and the second activeregion.
 11. The composite transistor according to claim 4, wherein thefirst active region and the second active region include atwo-dimensional material or graphene.
 12. The composite transistoraccording to claim 11, wherein a first interlayer insulation layer isprovided between the first A active region and the first B activeregion, and a second interlayer insulation layer is provided between thesecond A active region and the second B active region.
 13. The compositetransistor according to claim 10, wherein a first interlayer insulationlayer is provided between the first A active region and the first Bactive region, and a second interlayer insulation layer is providedbetween the second A active region and the second B active region.
 14. Acomposite transistor, comprising: a control electrode; a firstelectrode; a second electrode; a third electrode; a first A extendingpart, wherein the first A extending part extends from the firstelectrode to a first channel forming region; a second A extending part,wherein the second A extending part extends from the second electrode toa second channel forming region; a first B extending part, wherein thefirst B extending part extends from the third electrode to the firstchannel forming region; a second B extending part, wherein the second Bextending part extends from the third electrode to the second channelforming region.
 15. The composite transistor according to claim 14,wherein the first channel forming region is disposed on a first virtualplane, and wherein the second channel forming region is disposed on asecond virtual plane.
 16. The composite transistor according to claim15, wherein the first channel forming region is disposed between thecontrol electrode and the second channel forming region.
 16. Thecomposite transistor according to claim 14, wherein the first transistorbecomes conductive and the second transistor becomes non-conductive whenthe first electrode is given a voltage higher than a voltage given tothe second electrode and the control electrode is given a first voltage,and the second transistor becomes conductive and the first transistorbecomes non-conductive when the control electrode is given a secondvoltage higher than the first voltage.
 17. The composite transistor ofclaim 14, wherein the first active region and the second active regioninclude a two-dimensional material or graphene.
 18. The compositetransistor according to claim 14, wherein a second insulation layer isprovided between the first active region and the second active region.19. The composite transistor of claim 18, wherein the first activeregion and the second active region include a two-dimensional materialor graphene.